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#81
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I didn't mean to take over as the resident expert here, others that are watching along please jump in (and let us know if you disagree!)
The numbers look fine. Maybe a bit lower than optimum but you should have no problem with pump gas. I would have been much more concerned if they were very high. And readings are pretty consistent between cylinders. The carb not being locked open shouldn't have made much of a difference. My bet is that the engine should run good once you get past tuning. If those are 061 heads then my guess is that it has dished pistons, or a very long duration cam. Or something else was done to get compression down. But all we can do is guess for now. Next step is to get the timing right since timing can affect the vacuum reading if it is way off. The goal should be to get all-in timing around 34-36 deg. Depending on the weights/springs in the distributor and assuming it is working right you may get anywhere from around 8 to maybe 16 deg at idle with all-in adjusted in 34-36 range. If not then you can add distributor advance curve work to your to-do list. Hoping that you have adjusted timing before so know the drill. If you are not sure how to do it then ask questions! This is fun stuff- wish I was there! Yes the plug does look kind of ugly, but not sure how much you have run it at idle and how far off things are. Plug reading is definitely not an area of expertise for me.
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1969 Lemans vert, matador red, 462 CI, 3.07 12-bolt posi 1974 455 TA, admiralty blue/red interior HPP "cover car" - sold "The best way to show a car is to drive it" Last edited by PontGuy; 03-05-2014 at 08:24 PM. |
#82
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No need to apologise..there are a lot of helpful people on here. Since October I have made a tonne of threads and everyone has been more than willing to help. Got semi-scammed on a purchase so I have to spend my winter working out the kinks. Now back to the thread..
Glad the numbers look okay. I know this has been a question for many since I posted here. That being said will just regular grade gas be fine? Ya I have been under the impression to do everything first, and then timing. Either way I can go back to it for a second time around. I have never done timing (in fact just bought a timing light and other goodies when I went to Oklahoma last week) I have read a lot of write-ups from Pontiac forums (not sure if "Lars" is on this forum, but he emailed me a killer write-up about the Pontiac 400 and setting the timing). Not saying I won't have any questions though. What a big problem with me is (there are too many to mention) is that I don't really understand carbs and how they work/how to baby them. Likely some of the issues that I have had starting it/keeping it running are me not knowing how to properly work a carb with a manual choke. Not going to lie I was always under the impression that I pull the cable out to start it and push it in once it is warmed up. Well today I started it with the knob out, let it warm up, and pushed the knob in, causing the RPM to go way up to an RPM that doesn't make sense to drive at. I would have thought knob out would cause the RPM to be higher for it to start/warm up, and when the knob is pushed it it should cause the RPM to lower....apparently not. I am tempted to buy a new carb with electric choke just to save myself this stuff. Not to mention I have an Edelbrock 1405, and the instructions I have seen for tuning it are really shotty Ya, not sure about the spark plugs, but wow they are dark for having 0 miles driven on them Quote:
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#83
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Well it has been fun today, but will not be able to keep the lead indefinitely so someone else will need to step in eventually.
Can't say on the gas grade, we haven't got into dynamic compression yet- another lesson for later I'd start with premium, get it running good, then try mid-grade. Not so sure about regular but might be OK. Glad to hear you already have good instructions on setting the timing. If the engine is running then no real reason to put it off. The last time I had a "newbie's" car in my garage for a checkout the timing was way, way, way retarded. So far off that I was afraid to advance it all the way to 36 deg without test driving it half-way there. Made a huge difference in the way the engine ran. Not sure what to say about the carb- not exactly a light topic for someone new to them. Other than the idle does it seem to work OK? FYI pulling the choke closes the choke flap and also increases the idle speed by raising the throttle position using detents on the choke assembly. Pushing the knob back in opens the choke flap but the idle speed does not reset until you step on the gas a bit. So the engine speed increases. Perfectly normal. The plugs may clean up when you go for a drive with everything set right. Cold idling does not do them much good.
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1969 Lemans vert, matador red, 462 CI, 3.07 12-bolt posi 1974 455 TA, admiralty blue/red interior HPP "cover car" - sold "The best way to show a car is to drive it" |
#84
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Thanks for the help. Glad the compression test ended up okay. I have 3 days off starting tomorrow so time to get down and get the carb tuned/timing set so I know where I stand
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#85
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Just re-read all of this.
Stuck in front of a computer at home working all day this week, and helping you out made for some good breaks yesterday. Guess we can keep on going if you have more questions. Another mention on the carb choke. Once you get it running you can adjust the knob in or out to get a smooth idle while it warms up. When you are ready to drive you push it in and hit the gas a bit and it should slow down. Not sure about the Edelbrock but it probably has multiple detents so that you can push the knob in partially and slow the idle down some, but not all the way to normal. With an electric choke the above happens sort of automatically. But you still have to step on the gas to set the choke, and then again to get it off the fast idle detent once it warms up. Its just not like today's computer-controlled fuel injection. I never owned an Edelbrock carb so not sure how they are put together, and how good the idle circuit is. But I would make sure the timing is set reasonably right before making any adjustments to it.
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1969 Lemans vert, matador red, 462 CI, 3.07 12-bolt posi 1974 455 TA, admiralty blue/red interior HPP "cover car" - sold "The best way to show a car is to drive it" |
#86
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Do you guys remove the dist springs prior to setting the timing? I have read/heard two schools of thought on this, and will just do what the Pontiackers here do.
And I did a quick timing check yesterday....way off from my unprofessional observation. The notch on the balancer was significantly towards the passenger side away from the timing tab. Last edited by Darth Menace; 03-06-2014 at 03:36 PM. |
#87
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Darth- No, don't remove the springs. Just disconnect the vacuum advance. And run the engine up until the centrifugal advance is all-in to get your all-in reading. I've heard of the suggestion to remove them to get all-in but I've always thought it best to measure with the springs on since that is what the engine will actually see. It should be all-in well before 3500 RPM and probably much sooner than that. 3000 RPM is sort of typical.
Did you disconnect the vacuum advance before doing your quick check? The vacuum adds a bunch of advance, so you can't tell what you have with it connected.
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1969 Lemans vert, matador red, 462 CI, 3.07 12-bolt posi 1974 455 TA, admiralty blue/red interior HPP "cover car" - sold "The best way to show a car is to drive it" |
#88
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Darth,
Did you buy a "dial back" style timing light? With that type of timing light if you want initial timing at, say 12 BTDC, then with vacuum advance hose disconnected from distributor and hose plugged (golf tees work well for me to plug the hose), you set the light to 12 BTDC and when you point the light at the balancer (obviously with car running) the timing mark should be at zero on the pointer tab. If not you can roll the dial back switch until you get the mark at zero on the pointer tab and then look at the reading on the timing light to see what your initial timing is. Kind of a guess without this type of timing light or a degreed balancer. To adjust the timing, set the dial back to 12 BTDC and with the distributor hold down clamp bolt (9/16 IIRC) slightly loosened, and with the car running, turn the distributor (small increments) until you get the mark to zero. Your initial timing will now be 12 BTDC (assuming that's your spec you want). You can connect the vacuum hose back and now read the amount of vacuum advance you get (assuming you are using manifold vacuum) by using the dial back feature and using the new reading once the timing mark is at zero mark. Good way to test that the vacuum advance canister is working. If you are using ported vacuum you wouldn't see this vacuum advance until above idle. I don't bother disconnecting the distributor advance springs (although it seems to be a good way to check total advance safer). To do this I plug the vacuum line again, rev the engine up while watching the timing mark. When it stops advancing I note the RPM and dial back the timing light until the mark is again at zero. The reading will tell me the total advance (initial and mechanical advance) and at what RPM it is all in. Clear as mud? lol The dial back type timing light is relatively new technology but if you have a standard type timing light the steps are the same except you have to determing where the timing mark lines up with the pointer.
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1968 LeMans conv. 350 HO - 4 speed triple white (hear it idle here) https://www.youtube.com/watch?v=eVmq...ature=youtu.be 1968 LeMans conv. 350 - 4 speed Solar red/pearl |
#89
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nytrainer, thanks for putting together the very good write-up for Darth! I've been having fun but feeling a bit lonely.
I finally bought my first dial-back timing light last year- well worth it! My 30 year old light is now retired and in the same cabinet as the 50 year old one. Anyone here remember when they actually used the ignition power to light up instead of hooking up to the battery? Not sure why I still keep that one around...
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1969 Lemans vert, matador red, 462 CI, 3.07 12-bolt posi 1974 455 TA, admiralty blue/red interior HPP "cover car" - sold "The best way to show a car is to drive it" |
#90
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We'll get Darth on track.. Next thing you know he'll sell the Viper and pick up a round port!
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#91
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I have a xenon timing light with advance. So ultimately I can set the dial to 36, and at the all in timing the notch should line up with the 0. If thats the way it is then all is good and I will be doing it tonight.
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#92
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#93
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The Viper is epic and I have no plans on selling it. No matter where you drive there is someone snapping a cell-phone pic. I love it. |
#94
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Yeah the Viper. While you guys are working out the ignition timing I have to tell my Viper story. I had a friend a few years back that was into buying and selling used high-$$ performance cars. It was great fun for me because I got to drive cars that people dream about. Mostly European exotics, but he also liked Shelby's and had a 67 Cobra GT500 (just like Elanor) for a while. But the baddest car he ever bought was a Viper that was re-worked by the Shelby shop. Carroll even signed the dash. The torque and power were insane, actually very scary for a street car. And it had the most incredible sounding racing lope. The European cars were fun, but in my mind the Viper was the real deal. I really wanted that car but no way I could justify the cost, especially for a car that was barely street-worthy. Since then I've always wondered what a normal (not race-prepped) Viper is like but never have had the opportunity to drive one. Wish you were bit closer Darth
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1969 Lemans vert, matador red, 462 CI, 3.07 12-bolt posi 1974 455 TA, admiralty blue/red interior HPP "cover car" - sold "The best way to show a car is to drive it" |
#95
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Well I don't fit in a Viper but they are sure nice to look at lol. Round ports are the Ram Air IV, 455 HO, etc.. Pontiacs. Figured you'd be an ace on these cars soon and you'd swap the Viper (jk).
Many of the new timing lights (like the one you bought) also have RPM function so it makes the job real easy. Not sure what the specs on your engine would be but 36 degrees total (initial & mechanical) isn't set in stone so just measure what you have (you can set the light to 36 but adjust it to set the mark at zero) and see what you have after you bring up the rpm's. My 350 HO likes 33 total all in by 2500 for example. The adjustability is going to be the initial setting (w/o vacuum advance) and the rate (springs) at which full advance happens. So if the distributor is capable of a 20 degree centrifugal advance at 2800 rpm you would need 16 degrees initial advance if you were shooting for a total of 36. I think you have a good grasp on the concept.
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1968 LeMans conv. 350 HO - 4 speed triple white (hear it idle here) https://www.youtube.com/watch?v=eVmq...ature=youtu.be 1968 LeMans conv. 350 - 4 speed Solar red/pearl Last edited by nytrainer; 03-06-2014 at 07:23 PM. |
#96
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A few years ago when I was moving from a rural dump in Canada to Edmonton, AB I decided I wanted to buy a sports car. I had two mustangs when I was youger, a 93 mustang 5.0 (yay) and a 76 mustang II (boo!) so I have been a mustang fan, but they seem to be everywhere. So I leaned towards a used Vette, but I was drawn to the crazy curves and rare-ness of the Viper. Thanks to the bad economy of a lot of the USA, these cars aren't easy sells, so I bought this off ebay for $31.7k with 18xxx miles. It was a California car for most it's life, one buyer brought it to wyoming, and then I got it shipped to the Montana border and drove it home from there (The Custom S story is similar, but not near as happy). The only negative thing about the car is that performance parts are crazy expensive. All I can afford is to buy someone's used parts (bought a used magnaflow catback last winter, and some 2008 rims/wheels locally). Part of the draw towards getting an old muscle car is the cheapness in parts....I an tinker on it and not break the bank. Now I just have to find a used set of headers for the Viper..I hear it really makes them angry |
#97
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Been on and off and I missed this thread too, just caught up on it. wow, I'll join the crowd with the comments - why can't you live closer!?! I'd be over there tomorrow!
So what's the verdict on the timing? I'll have to say I feel left behind in the times with this discussion of all in timing and new timing lights that have these digital settings on them. I guess I'm still lost in the past with disconnecting the advance, connecting the tach, and setting the dwell to 30 and the initial timing. unless I missed it, you're still running points correct? (all my cars still run points, I still don't see the benefit to HEI for a regular street driver) One thing I keep seeing is the 12 BTC being tossed out there for initial timing. I've got a pair of AC Delco factory tune up manuals. The 1969 manual says all 67 were 6 degrees btc, the 71 manual shows 67 400 at 9 degrees so not sure why they changed that but they didn't get into the 12's until the low compression motors in 71. Just be careful that you don't get yourself into the over advanced land that you get it running right where you want it and create the dreaded "hot start" issue that everyone then mis-diagnoses as a bad starter or cables when it's really an over-advanced timing situation. |
#98
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Alrighty, so here goes. My first timing episode.
Turned on the car, let it warm up, pulled the vacuum advance, choke fully open. All out timing was set at 26. So I ended up setting it at 36 and decided to tighten the distributor bolt, and then when I did i set it all out of whack again Anyway, eventually got it set to 36 and got it tightened down without messing it up again. As far as I can tell (which isn't much) it seemed good. Prior to this I would often stall when going into drive, but it didn't (progress for sure). My only gripe is when I put it into reverse the rpm went down a bit lower sounding as though it was close to stalling. I am assuming I just have to raise the idle a bit (I don't have a tach yet so maybe the idle is a bit low, plus next step is the carb adjustment so maybe all that will settle out in the end. Overall not a big worry in my books) So ya, who knows if it's 100% right, but it runs much much better than it did before (going by the little amount I drove it today since it's not plated. Down the driveway, u-turn about 50 feet down and back into the driveway.) |
#99
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Darth,
GTO4ever brings up a good point. As I mentioned I do not know the specs for your engine so any numbers I used in my examples were just that...examples. My 68 350 HO factory initial spec is 9 BTDC. If you're not sure of the specs throw the question out there. Vehicle weight, tire size, rear axle ratio, fuel quality, carb. settings, automatic trans. etc.. will be considered when fine tuning your timing. Many run the same combo as you so you can get a better idea where you want to be if you ask.
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1968 LeMans conv. 350 HO - 4 speed triple white (hear it idle here) https://www.youtube.com/watch?v=eVmq...ature=youtu.be 1968 LeMans conv. 350 - 4 speed Solar red/pearl |
#100
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Funny thing is I set the all out timing at 36, but totally forgot to check the timing at idle. Ah well...something to do later. |
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